In a typical dental or medical 3D camera or scanner imaging system, a series of two-dimensional (2D) intensity images of one or more object surfaces in an object scene is acquired where the illumination for each image may vary. In some systems, structured light patterns are projected onto the surface and detected in each 2D intensity image. For example, the projected light pattern can be generated by projecting a pair of coherent optical beams onto the object surface and the resulting fringe pattern varied between successive 2D images. Alternatively, the projected light pattern may be a series of projected parallel lines generated using an intensity mask and the projected pattern shifted in position between successive 2D images. In still other types of 3D imaging systems, techniques such as confocal imaging are employed.
In a dynamic 3D imaging system, a series of 3D data sets is acquired while the camera or scanner is in motion relative to the object scene. For example, the imaging system can be a wand or other handheld device that a user manually positions relative to the object scene. In some applications, multiple objects surfaces are measured by moving the device relative to the objects so that surfaces obscured from view of the device in one position are observable by the device in another position. For example, in dental applications the presence of teeth or other dental features in a static view can obscure the view of other teeth. A processing unit registers the overlapped region of all acquired 3D data to obtain a full 3D data set representation of all surfaces observed during the measurement procedure.
The results of a 3D measurement can be difficult to interpret. For example, measurements of an intra-oral cavity typically include 3D data for different classes of objects such as teeth, artificial dental structures and gingiva. The 3D data can be presented to a user in different graphical formats such as a display of the points in the form of a 3D surface map representation or in the form of a 3D point cloud. Differentiating between different structures represented in the display can be problematic and may require extensive effort to properly interpret features in the display. In some instances, the clinician may be unable to distinguish adjacent portions of separate objects. For example, it can be difficult for a dental professional to accurately recognize the boundary between gingiva and enamel or dentin.